Color negative origination silver halide photographic films are a class of photosensitive materials that map the luminance (neutral) and chrominance (color) information of a scene to complementary tonal and hue polarities in the negative film. Upon exposure and development of the film to form dye images from photographic couplers incorporated in the film, light areas of the scene are recorded as dark areas on the color negative film, and dark areas of the scene are recorded as light areas on the color negative film. Colored areas of the scene are typically recorded as complementary colors in the color negative film: red is recorded as cyan, green is recorded as magenta, blue is recorded as yellow, etc. In order to render an accurate reproduction of a scene, a subsequent process is necessary to reverse the luminance and chrominance information back to those of the original scene. In the motion picture industry, one such subsequent process is to optically print (by contact or optics) the color negative film onto another negative working photosensitive silver halide material which produces dye images upon exposure and development, such as a motion picture silver halide print film, to produce a color positive image suitable for projection.
Historically, color print silver halide photographic materials, such as EASTMAN EXR Color Print Film 5386.TM., have been optimized to yield pleasing projected prints when used in conjunction with color negative origination silver halide photographic materials as discussed above. That is, the sensitometric properties of print materials are co-optimized by considering the properties of the printing device to be used and the nature of a representative color negative tone scale to be printed, such as that of KODAK VISION 500T Color Negative Film 5279.TM.. When a motion picture color negative is printed on motion picture color print stock, the sensitometric properties of the two materials combine to yield an acceptable scene reproduction in the print film when projected on a theater screen. To facilitate obtaining optimal reproductions, guidelines exist regarding the exposure of the camera original negative (for example see American Cinematographer Manual, Dr. Rod Ryan Ed., 7th Edition, The ASC Press, Hollywood, Calif., 1993, pp128-141.), exposure of the print stock (LAD--Laboratory Aim Density KODAK Publication No. H-6 1), and projector/screen luminance levels (Society of Motion Picture and Television Engineers (SMPTE) Standard 196M-1995).
In order to obtain a high quality visual image in an optical photographic print, the contrasts for each color record of the negative film and print film designed for producing optical prints are conventionally maintained within certain ranges (e.g., mid-scale contrasts of about 0.45-0.7 for negative films and about 2.5-3.1 for print films), as too low a contrast may result in production of flat-looking positive print images with black tones rendered as smokey-grey and white tones rendered as light gray, while too high a contrast may result in poor flesh tone reproductions and loss of shadow detail. Pictures such as these would not be pleasing to view and would be deemed to be of low quality in the industry.
Correct exposure of camera negative originals has long been emphasized not only to ensure that critical scene information is properly recorded but also so that when the negative is printed on a photographic print film according to trade practice, scene blacks are sufficiently dense in the resulting projected prints. The importance of obtaining substantial black densities is such that cinematographers often over-expose camera negatives as a means of obtaining good blacks. Dense camera originals require higher light levels to be used in the printing step. When the printing light is increased, the exposure delivered to the photographic print film from the Dmin area of the camera film is higher, resulting in greater dye generation upon photographic processing and resulting higher black densities. This effect is well known in the trade (American Cinematographer Manual, p281). Even with overexposure techniques, however, maximum equivalent neutral (i.e., visual) densities obtainable for conventional silver halide photographic print films are generally limited to about 3.8, where the Equivalent Neutral Density of any particular dye color record is defined as the visual density that results when the other two dyes are added in quantities just sufficient to produce a neutral gray (see, e.g., "Procedures for Equivalent-Neutral-Density (END) Calibration of Color Densitometers Using a Digital Computer", by Albert J. Sant, in the Photographic Science and Engineering, Vol. 14, Number 5, September-October 1970, pg. 356). Over-exposures additionally can result in loss of highlight detail in a resulting print.
Special photographic film image processing techniques are also known in the art for raising black density levels in conventional photographic silver halide print materials, such as by-passing the bleach step present in normal print processing so as to retain developed silver (see, e.g., B. Bergery, "Reflections: The Lab, Part II", American Cinematographer, May 1993, pp. 74-78). The retained silver increases print opacity yielding higher black densities, with an accompanying loss of color saturation. Many photographers and cinematographers often desire to mute colors without sacrificing neutral tone scale, which would result in poor black and shadow rendition. The bleach by-pass process has accordingly become popular in the motion picture industry, as in addition to giving an increase in black density, it also results in a decrease in color saturation, which cinematographers may use to obtain a desired "desaturated" color look in the resulting processed print to help establish certain moods with a film. Given the need for large throughput in the creation of theatrical release prints, however, non-standard processing associated with bleach by-pass is burdensome and impractical.
Copending, commonly assigned U.S. Application Ser. No. 08/931,010, the disclosure of which is incorporated by reference herein, discloses color-coupled silver halide photographic print film elements which enable higher black densities and color saturation, while also providing good flesh and shadow-detail reproduction. This is achieved through design of a color print film silver halide photographic element having sufficiently high silver and coupler levels and overall contrast values in the color records to obtain relatively high maximum densities, where comparatively high upper-scale contrast values are used while maintaining relatively low mid-scale contrast values. Such elements may be used in current printers and processors to obtain such properties without requiring any modifications to standard exposure and development processes. Such elements, however, do not provide the desaturated color look associated with bleach by-pass processing of conventional print films.
U.S. Pat. No. 5,491,053 discloses the use of image dye-forming coupler mixing in motion picture films in order to achieve a "chromogenic" black and white (i.e., color neutral) image upon processing with a color developing agent. The neutral images obtained therein are intended to replicate black and white film images conventionally obtained by developing exposed silver halide in a black-and-white developer (such as hydroquinone) to form a silver image.
It would be desirable to provide a color-coupled silver halide photographic color print film element which would enable a desaturated color image, while also desirably providing good flesh contrast and shadow reproduction and without sacrificing neutral tone scale. It would be further desirable to provide such an element which may be used with conventional printer set-ups and standard processing conditions.